Honestly, there are cookies which using web browser to connect back to mothership, your computer will be control during idle time. They install software to bypass Internet Security, collect password and via back to mothership.

It's at malwarebytes.org There's a free version that does on demand scanning and their forums are very good at solving problems. You can buy a lifetime license for cheap to get active protection. It's designed to work with and not conflict with major AV programs and security suites. It doesn't replace traditional AV programs as Malwarebytes doesn't bother with older file signature based issues. Kooky name, great product.